From the Guidelines
The treatment approach for a patient with a positive NMDA receptor antibody titer and abnormal clinical symptoms involves a multi-faceted strategy focusing on immunotherapy and tumor removal if present. First-line immunotherapy typically includes high-dose corticosteroids (methylprednisolone 1g daily for 3-5 days), intravenous immunoglobulin (IVIG at 2g/kg divided over 5 days), and/or plasma exchange (5-7 exchanges over 10-14 days) as suggested by 1. These treatments aim to reduce antibody levels and suppress the immune response. Comprehensive tumor screening is essential, as many cases are paraneoplastic, particularly ovarian teratomas in young women, as highlighted in 1. If a tumor is identified, surgical removal is crucial for recovery. For patients who don't respond adequately to first-line treatments within 2-3 weeks, second-line immunotherapy should be initiated, including rituximab (375 mg/m² weekly for 4 weeks) and/or cyclophosphamide (750 mg/m² monthly for 3-6 months) as recommended in 1. Symptomatic management is also important, with antipsychotics for behavioral symptoms, benzodiazepines for anxiety and catatonia, and antiepileptic drugs for seizures. Most patients require ICU care during the acute phase due to autonomic instability, hypoventilation, or decreased consciousness. Long-term immunosuppression for 1-2 years may be necessary to prevent relapses, with approximately 75% of patients achieving substantial recovery, though rehabilitation is often needed for residual cognitive deficits. Key considerations include:
- Early initiation of immunotherapy and tumor screening
- Use of combination therapies for severe cases
- Monitoring for relapses and adjustment of treatment as necessary
- Symptomatic management to address behavioral, anxiety, and seizure symptoms. Given the complexity and variability of autoimmune encephalitis, a personalized approach considering the patient's specific clinical presentation, antibody status, and response to initial treatments is crucial, as emphasized in 1.
From the Research
Treatment Approach for NMDA Receptor Antibody Titer and Abnormal Clinical Symptoms
- The treatment approach for a patient with a positive NMDA receptor antibody titer and abnormal clinical symptoms typically involves immunotherapy and tumor resection, if present 2.
- First-line therapy may include intravenous immunoglobulin (IVIG) therapy, plasmapheresis, methylprednisolone, and bilateral salpingoophorectomy 2.
- Second-line immunotherapy with cyclophosphamide and rituximab may be administered if there is no clinical improvement with first-line treatment 2, 3.
- The efficacy of treatment for male patients without tumor may include plasmapheresis, plasma exchange, rituximab, or cyclophosphamide, with similar efficacy rates to intravenous immunoglobulin 4.
- Diagnosis of anti-NMDA receptor encephalitis after Herpes simplex virus-associated encephalitis is often delayed, and treatment consists of steroids, plasma exchange, and rituximab 5.
- There is no standardized approach to immunotherapy, but areas of practice uniformity include first-line treatment with intravenous immunoglobulin and intravenous methylprednisone, and initiation of disease-modifying therapy with rituximab alone 6.
Key Considerations
- Patients with anti-NMDA receptor encephalitis can develop severe autonomic dysfunction, including bradycardia and asystole, which may require placement of permanent cardiac pacemakers 2.
- Elevated intracranial pressure may also be associated with anti-NMDA receptor encephalitis and contribute to autonomic instability 2.
- Recovery from severe frontotemporal dysfunction can occur after delayed treatment, and spontaneous recovery independent of therapy is possible 3.
- B-cell attracting C-X-C motif chemokine 13 (CXCL13) and microRNA let-7b may have potential as treatment response biomarkers for anti-NMDA receptor encephalitis 4.